Diaphragm pump rocker arms



Nmr. 25, 1959 M. NOIROT ET AL 3,479,928

DIAPHRAGM PUMP ROCKER ARMS Filed Dec. 4, 1967 2 Sheets-Sheet 1 ZZZ K/za/WWI "vi a A Home y Nov. 25, 1969 M. NOIROT E AL 3,479,923

DIAPHRAGM PUMP ROCKER ARMS Filed Dec. 4, 1967 2 Sheets-Sheet 2 INVENTORS'1 ga Attorney 3,479,928 DIAPIRAGM PUMP ROCKER ARMS Michel Noirot,Chelles, and Claude Quatredeniers, Les

lLilas, France, assignors to General Motors Corporation, Detroit, Mich,a corporation of Delaware Filed Dec. 4, 1967, Ser. No. 687,706 Claimspriority, application Great Britain, Dec. 6, 1966, 54,527/ 66 Int. (ll.F163 1/10; F04b 43/02; F16h 53/06 US. Cl. 92129 2 Claims ABSTRACT OF THEDISCLOSURE The rocker arm of a diaphragm pump for use as an internalcombustion engine fuel pump is made with a metal core one end of whichis engageable with a rotary drive cam and the other end of which hasmoulded integral therewith an arm portion, of nylon or other plasticsmaterial, a free end of which is forked for engagement with the pumpdiaphragm push rod.

This invention relates to diaphragm pump rocker arms and in particularto a rocker arm for a. diaphragm pump of the kind such as is commonlyused as a fuel pump for an internal combustion engine.

In such pumps the reciprocatory diaphragm is commonly arranged foractuation by a rocker arm, one end of which engages a rotary cam or likemember driven by the engine and the other end of which engages a pushrod secured to the centre of the diaphragm.

A diaphragm pump rocker arm according to the invention comprises anelongate metal core one end of which is adapted to be engaged with a camor other drive mem her and the other end of which has moulded integraltherewith an arm portion of plastics material a free end of which isadapted to be engaged with the diaphragm push rod.

The rocker arm has intermediate its ends a transverse bore which formsthe journal for a pivot pin on which the rocker arm is mounted in thepump housing.

Intermediate its ends the rocker arm is also formed with a support forone end of a spring by which said one end of the rocker arm is pressedinto engagement with the cam or other drive member; the support mayeither be moulded as an integral part of said arm portion of plasticsmaterial, or may be formed as an integral part of said core.

The scope of the invention is defined by the appended claims; and theinvention and the method by which it is to be performed are hereinafterparticularly described with reference to the accompanying drawings inwhich:

FIGURE 1 is a perspective view of a diaphragm pump rocker arm theopposite ends of which are respectively engaged with a pump diaphragmpush rod and an actuator cam;

FIGURE 2 is an enlarged longitudinal section through part of the rockerarm shown in FIGURE 1;

FIGURE 3 is a section on the line 33 of FIGURE 2; and

FIGURE 4 is a perspective view of a modified form of construction of therocker arm shown in FIGURE 1.

FIGURES 1 to 3 show a preferred embodiment of the invention in which arocker arm 1 has a steel core 2, which may be formed as a single part asshown, or may nited States Patent M we be of laminated construction, oneend of the core 2 of the arm being formed as a cam follower 3 adapted toengage a rotary cam 4. At its other end the core 2 of the arm has aportion 5 of plastics material, for example, nylon moulded therearound,the free end of the arm portion 5 being forked as shown at 6 to engageabout a push rod 7 for the pump diaphragm, and to abut a washer 8 ofrelatively soft resilient material which overlies a disc 9 of metalsecured at the end of the push rod 7.

The other parts of the pump are omitted for the sake of simplicity andas their construction will be well understood by those skilled in theart.

Intermediate its ends the rocker arm 1 has a transverse bore 10 in whichcan be journalled a pivot pin 13, the bore 10 extending through theplastics portion 5 and the core 2.

A return spring 11 is adapted to press the rocker arm 1 into engagementwith the cam 4 and in the embodiment shown in FIGURES 1 to 3 the rockerarm plastics portion 5 is formed with an integral support 12 for one endof the spring 11.

As shown in FIGURES 2 and 3 the core of the rocker arm is formed with anaperture 14 therein intermediate the bore 10 and the forked end 6, toprovide an interlock with the plastics material moulded thereon and isalso formed with further openings 15 and 16 which are adapted to beengaged by location pins in a mould during the operation of moulding theplastics material about the core.

As shown in FIGURES 2 and 3 the bore 10 is formed in a portion of theplastics material which extends through an opening 17 in the core 2 andprojects to either side thereof to form annular shoulders 18, therebyensuring that there is an adequate surface area to provide a goodbearing surface in the bore 10.

As shown in the modified embodiment of the invention illustrated inFIGURE 4, the spring 11 may be mounted on an integral part of the core 2instead of on a support integral with the plastics portion 5 of the arm.In other respects the construction shown in FIGURE 4 is the same as thatshown in FIGURE 1 and the parts thereof bear similar reference numerals.

The forms of construction of the diaphragm pump rocker arm described andillustrated simplify manufacture of the rocker arm and reduce the costof the tools required for manufacture; the use of such a rocker arm indiaphragm pump results in desirable reduction in the noise of operationthereof.

We claim:

1. In a diaphragm fuel pump having an improved rocker arm comprising ametal core having one end adapted to engage a rotary cam, the other endof said core having an integrally molded arm portion thereon, saidmolded arm portion extending beyond said metal core to form a free endwith said free end adapted to engage a diaphragm push rod on saiddiaphragm fuel pump, said metal core having a transverse bore whereinsaid molded arm portion extends through and to each side of thetransverse bore in said metal core to form a journal for a pivot pin onwhich said rocker arm is mounted in said diaphragm fuel pump, supportmeans on said rocker arm in engagement with a spring on said diaphragmpump with said one end of said metal core being pressed into engagementwith said rotary cam by said spring.

3 4 a 2. In a diaphragm fuel pump having an improved 3,339,989 9/1967Kraus 30872 rocker arm as set forth in claim 1, said support means3,362,250 1/1968 Bradley 74-569 being an integral part of said moldedarm portion. 3,186,351 6/1965 Bradley 103-150 References Cited FOREIGNPATENTS UNITED STATES PATENTS 520,903 5/1940 Great Britain.

7/1959 McDufiie 74-569 6/1962 Schmio WILLIAM L. FREEH, Primary Examlner7/1963 Elfes 103--213 X 12/1958 Katcher 103213 X 10 11/1966 Tucker308-72 74-569; 103150; 3081

